1. Field of the Invention
The present invention relates to a belt apparatus. More specifically, the present invention relates to a belt clutch apparatus, an intermediate transfer belt with the clutch, and an image forming apparatus with the intermediate transfer belt.
2. Description of the Related Art
In general, the operation range of a belt apparatus is determined by a plurality of rollers rotatably installed therein. The belt apparatus serves a wide range of applications such as supplying power to other units that are separated by a predetermined distance or carrying substances during rotation. Generally, in an image forming apparatus for printing color images, the belt is positioned between a developing unit and a printing paper for carrying developer. Particularly, the belt apparatus typically used is called an intermediate transfer belt. FIG. 1 is a schematic view of the color image forming apparatus, which includes a plurality of photosensitive drums for each color, and an intermediate transfer belt for transferring visible images from the photosensitive drums.
As shown in FIG. 1, the color image forming apparatus 1 includes a paper feeding unit 10, a carriage unit 20, a developing unit 30, an intermediate transfer belt 40, a fusing unit 50, and a delivery unit 60.
The paper feeding unit 10 picks up a piece of paper being received, and feeds (or supplies) the paper to the carriage unit 20.
The carriage unit 20 carries the paper to the intermediate transfer belt 40.
The developing unit 30 includes (as shown, e.g., in FIG. 1) four developing cartridges, each having a developing roller and a photosensitive medium, e.g., a photosensitive drum (e.g., 32C, 32M, 32Y, and 32B), so that cyan, magenta, yellow and black developers can be developed individually on the four respectively corresponding photosensitive mediums. When the photosensitive mediums with a visible image formed thereon according to colors are brought in contact with the intermediate transfer belt 40, they rotate and are layered sequentially on the surface of the intermediate transfer belt 40 to form a color image.
The intermediate transfer belt 40 includes a plurality of rollers configured for driving. Usually, the intermediate transfer belt 40 rotates with a backup roller 41, and transfers a color image transmitted from the developing unit 30 onto the printing paper being carried by the carriage unit 20.
The fusing unit 50 applies high temperature and high pressure to the printing paper bearing the visible image in order to fuse the transferred image onto the printing paper.
The delivery unit 60 delivers the printing paper with the color fused image thereon out of the image forming apparatus.
However, because the intermediate transfer belt 40 always rotates in contact with the developing unit 30 and the backup roller 41, it may easily wear out or abrade as the duration of use increases. Therefore, to extend lifespan of the intermediate transfer belt 40, it generally is best to minimize contact time with the developing unit 30 and the backup roller 41 for reducing abrasion as much as possible.
In practice, however, the operation range of the intermediate transfer belt 40 is fixed by a plurality of roller members. Once the operation range is set, it typically cannot be changed. Therefore, even during the cleaning operation, where there is no need for the intermediate transfer belt 40 to be in contact with the developing unit 30 and/or the backup roller 41, the intermediate transfer belt 40 is constantly driven in contact with the developing unit 30 and the backup roller 41.
Accordingly, there is a need for an improved image forming apparatus having which does not unnecessarily abrade the intermediate transfer belt 40.